Electrons (negatively charged particles) can flow through substances called conductors.
Graphite, used to make pencil lead, among other things, is a conductor and can be used to make a simple circuit on paper. A circuit is just a path for electrical current.
You have to do this experiment with a graphite pencil, rather than the kind you use at school, but you can pick them up at most art supply stores. You’ll also need a few small LED bulbs, 2 wires with alligator clips on either end, and a 9 volt battery.
Adult supervision recommended.
- Make a thick, black rectangle using a graphite pencil. We used a #9 graphite crayon.
- Hook the two wires up to the battery terminals.
- Clip the wire attached to the positive battery terminal to one wire of an LED bulb. (Don’t test it on the battery, or you may blow it out.)
4. Touch the un-attached LED wire to the other (left) side of the graphite bar.
5.Touch the alligator clip attached to the negative battery terminal to the right side of the graphite bar you drew.
6.If it doesn’t light, switch the positive alligator clip to the other wire of the LED bulb and try it again.
7. Move negative clip closer to the bulb. It should get brighter as you decrease the distance.
Repost from Dec.19th, 2010 (Photos from Kitchen Science Lab for Kids, Quarry Books 2014)
Have you ever gotten a shock from a doorknob after shuffling across a carpet? The term “static electricity” refers to the build-up of a positive or negative electrical charge on the surface of an object. In this case, the charged object is your body. You feel an electric shock as the charge you’ve collected from the carpet jumps from your hand to the metal doorknob.
Tiny particles called electrons have negative charges and can jump from object to object. When you rub a balloon on your hair, or a comb through it, many of these electrons are stripped from your hair and move to the balloon or comb giving it a negative charge (and often leaving your hair all positively charged and standing up as the strands try to avoid each other.)
The negatively charged balloon or comb then makes a great tool for making electrons jump around!
You can easily make a contraption called an electroscope using:
-some thin aluminum foil or mylar (the shiny stuff balloons and candy wrappers are made from)
-a balloon or comb.
- Cut the cardboard to fit over the mouth of the jar, poke the nail through the cardboard, tape on two long, thin strips of foil or mylar (see photo) and place the whole thing in the jar so the foil strips hang down, touching each other.
2. Charge your balloon or comb by rubbing it on your hair or clothing to give it a negative charge. Bring the charged object close to the nail head. You don’t even have to touch it!
What happened? Some negatively-charged electrons jump from the comb to the nail and into the strips of foil. The negative charge on the comb will push electrons (which are also negatively charged) down to the foil/mylar and give both strips a negative charge. The two strips try to move away from one another as the like charges repelled each other.
What happens when you make the strips out of different materials like paper? Are there other charged objects you can use to make your foil strips “dance”?
You can also bend a thin stream of water from the faucet by holding your charged comb next to it. The water is uncharged and is pulled toward the negative charge of the comb.
Try making small pieces of tissue paper float or dance by holding a charged comb or balloon next to them! We filled an empty soda bottle with tiny pieces of foil and made them jump around with a charged comb held close to the bottle.
(Re-post from April 14, 2016)
I love traditional tie-dye, but it’s fun to do this experiment that uses permanent markers and rubbing alcohol to make bright, gorgeous designs that mimic tie-dye, more easily, and with less mess.
This experiment was created by Bob Becker, a chemistry and AP chemistry teacher at Kirkwood High School in Kirkwood, MO. (To find a few of the original experiments I invented, check out Frankenworms, Sugar Cube Fizz Bombs, Homemade Window Stickies, Foaming Slime, and Cornstarch Frescos.)
Here’s a video from my YouTube channel on how to do this experiment, so kids can “watch and do.”
To play with permanent marker tie dye, you’ll need:
-permanent markers (like Sharpies)
-cotton items to decorate, like tee-shirts, socks, or dish towels
-rubbing alcohol (isopropanol)*Read warning labels. Parental supervision is required, since rubbing alcohol is poisonous if swallowed. Do this experiment in a well-ventilated area, and do not expose your artwork to heat until is is COMPLETELY dry, since rubbing alcohol and its fumes are flammable.
-containers like plastic cups or jars
To make your designs, stretch the cotton over the mouth of a jar or cup and secure it with rubber bands. (See video above.)
Use permanent markers to make several dime-sized dots of different colors on the stretched cotton.
Slowly drip rubbing alcohol onto the spots of color until the alcohol starts to soak outward, carrying the ink with it.
Allow your design to dry overnight. When completely dry, hang your shirt in the sun, or put it in the dryer for 15 minutes to set the color. Wash separately from other clothes, just in case!
The Science Behind the Fun: Pigments are molecules that give things color. The pigments in permanent markers are trapped in ink compounds that are insoluable in water, which means that they won’t dissolve in water. However, if you add a solvent, like rubbing alcohol, or isopropanol, to permanent markers, it dissolves the ink. As the alcohol moves through the cloth you are decorating, it carries the pigments along with it. Small pigment molecules move faster than big ones, so the colors sometimes separate into their different color components as they move through the cloth. The alcohol evaporates into the air, leaving the ink in the fabric, and since it is still insoluable in water, it won’t come out when you wash it.
Enrichment: What happens if you draw lines, concentric circles or different shapes on your designs? Can you layer colors and watch them separate? What if you add rubbing alcohol next to the color, instead of directly on it? How many drops of alcohol do you have to add to a dime-sized color spot before it starts to expand?
I grew up hearing the Chi Chi Chi Chi song on TV, but our family never actually purchased a Chi Pet, so I never realized the dream of sprouting green hair from a clay animal. Until now.
With the emergence of chi seeds as a new health fad, it’s easy to get your hands on some chi seeds (of the sprouting variety) with a click of the mouse, or a trip to the Co-op. Chia seeds are quick-growing members of the mint family called Salivia hispanica, hailing from Central and South America where they have served as a food source for humans for well over a thousand years. And although studies have shown that they probably won’t help you lose weight, they are chock full of protein, fiber, fatty acids and anti-oxidants.
When you give these tiny seeds the signals they need to sprout: water, light, warmth and air, they grow very fast, so you should see tiny white roots poking out in a few days, soon to be followed by a shoot and leaves.
Since most people don’t have any way to fire clay in their homes, I decided to keep it simple. These homemade chia pets are basically clay (or Play-Dough) animals formed around seed starter pellets (also available online.) Add a few pre-soaked chia seeds, wait a few days and Voila! Your homemade animal will be sprouting living green hair.
-2 Tbs chia (sprouting) seeds
-dirt or seed starter pellets
-clay or playdough
-a fork or toothpick
1. Soak 2 Tbs. chia seeds in 1/2 cup water overnight. The mixture will get slimy as it sits and water is trapped by tiny fibers on the seeds to form a gel-like substance.
2. The next day, soak your seed starter pellets per the instructions on the package.
3. Create a clay or Play-Dough animal big enough to hold the expanded pellet or some dirt inside, wherever you want the green sprouts to appear.
4. Put the dirt/seed starter pellet into to space you created and scratch the surface with a fork or toothpick.
5. Add 1/2 tsp or so of seeds to the dirt and use the fork or toothpick to mix them into the soil.
6. Wait for the seeds to grow, keeping the soil damp at all times. (You can speed growth by covering your chia pet with a plastic bag to hold in heat and moisture.) Watch for roots and leaves to emerge and draw or photograph them.
“No risk is more terrifying than that taken by the first root. A lucky root will eventually find water, but its first job is to anchor an embryo and forever end its mobile phase, however passive that motility was….it assesses the light and humidity of the moment, refers to its programming and quite literally takes the plunge.” -Hope Jahren “Lab Girl” (My favorite new book. Read it!)
Remember this homemade snow candy from Laura Ingalls Wilder’s classic “Little House in the Big Woods?” You can make the same amazing maple treats using heat evaporation and quick cooling in the snow, or on crushed ice cubes.
Here’s how to make the candy, along with some candy-making science, straight from the pages of my new book, “Outdoor Science Lab for Kids,” which you can order from your favorite book retailer by clicking here.
-1 cup pure maple syrup
-fresh, clean snow
Safety Tips and Hints:
-Hot sugar syrup can cause burns. This experiment must be done with adult supervision.
-Allow candy to cool completely before tasting.
-Only use pure maple syrup for the best results.
Step 1: Go outside and scout out a spot with some clean snow several inches deep for making your candy. Alternately, collect and pack down a few inches of fresh snow in a large, flat container, like a casserole dish. (You can use crushed ice cubes if you don’t have snow.)
Step 2. Boil the maple syrup in saucepan, stirring constantly until it reaches around 235-240 degrees F (soft ball stage.)
Step 3. Remove the maple syrup from the heat and carefully pour it into a heat-resistant container with a spout, like a Pyrex measuring cup.
Step 4. Pour wiggly candy lines into the snow to freeze them into shape.
Step 5. When you’re done, remove the candy from the snow with a fork.
Step 6. Eat your candy right away, or let it warm up and wind it around sticks or skewers to make maple lollipops. Enjoy!
The Science Behind the Fun:
Maple syrup is made from watery tree sap boiled to evaporate most of the moisture it contains when it’s first tapped from a tree. Following evaporation, the syrup that remains is mostly made up of a sugar called sucrose, but it also contains smaller amounts of glucose and fructose.
Naturally, other organic compounds are also present in tree sap, giving syrup from different areas unique flavors. Syrup collected earlier in spring when it is cold tend to be light in color and have a mild flavor. As the days get warmer, microbes ferment some of the sugar in the syrup, making it darker and giving it a more robust taste.
In this experiment, you heat maple syrup, evaporating even more water. A super saturated solution forms, which holds more sugar molecules in the liquid than would be possible if you evaporated the water at room temperature.
When you pour the supersaturated sugar into the snow, it cools quickly, forming some sugar crystals to give the maple candy a soft, semi-solid consistency. Heating the syrup to a higher temperature will evaporate more water, resulting in even more crystal formation in the cooled syrup, making it harder to bite. If you carefully evaporate all of the water from maple syrup, you’ll be left with pure maple sugar crystals.
-Try collecting some syrup from your pan at several different temperatures and compare the resulting snow candy for texture, color and consistency.
-Can you do the same experiment with other sugar syrups, like molasses or corn syrup?
-Try to make maple sugar.
Crying over broken candy canes? Cry no more. Make art!
My publisher recently sent me a copy of “Amazing (Mostly) Edible Science,” by Andrew Schloss. There are tons of fun experiments in the book, but Candy Cane Origami seemed like a perfect one to try during the holidays.
*Melted candy can get dangerously hot, so parental supervision is required!
-candy canes (broken or whole), wrappers removed
-heavy-duty aluminum foil
-a cookie sheet
-a wire cooling rack
What to do:
- Preheat oven to 250F.
- Cover cookie sheet with foil
- Place candy canes on foil, not touching each other
- Bake candy canes for around 10 minutes and have an adult check them. They should be stretchy, but not too hot to touch.
- When the candy canes are ready, bend, fold, twist and pull them into cool shapes. Try pulling one long and wrapping it around a chopstick to make a spiral. What else could you try?
- If the candy gets to brittle to work with, put it back in the oven for a few minutes to make it soft again.
The science behind the fun:
If you looks at the ingredients of candy canes, they’re usually made of table sugar (sucrose), corn syrup, flavoring, and food coloring. Glucose and fructose are sweet-tasting molecules that stick together to make up most of the sugars we eat, like table sugar (sucrose) and corn syrup. You can think of them as the building blocks of candy.
At room temperature, candy canes are hard and brittle, but adding heat changes the way the molecules behave. Both table sugar and corn syrup contain linked molecules of glucose and fructose, but corn syrup has much more fructose than glucose, and the fructose interferes with sugar crystal formation. According to Andrew Schloss, “the corn syrup has more fructose, which means the sugar crystals in the candy don’t fit tightly together. The crystals have space between them, which allows them to bend and move without cracking.”
Here’s a great article on the science of candy-making!
Buying gifts is fine, but it’s more fun to make them. This year, we decided to make botanical gifts for the adults on our list, and slime kits for the kids.
To make a slime kit, you’ll need:
-glitter glue (optional)
-Borax laundry detergent
-small plastic sample cups or paper cups (optional)
-jars with lids
-a small plastic bin or shoe box
-extra glitter (optional)
Label the jars and fill as follows:
- Bouncy Ball Mix (fill with glue)
- Slime Mix (fill with equal parts glue and water, mixed well)
- Borax detergent (fill with powdered detergent)
- Cross-Linking Solution (leave empty)
- optional-Sparkly Bouncy Ball mix (fill with glitter glue)
- optional-Sparkly Slime Mix (fill with equal parts water and glitter glue, mixed well)
Make an instruction sheet for the kit. (Print out the info below, or copy it onto a card.)
To make slime:
- Fill Cross-Linking Solution container with warm water. Add about 2 tsp Borax per 1/2 cup water to the container. Mix well. (Don’t worry if all the Borax doesn’t dissolve!)
- Add a few spoonfuls of Ball Mix or Slime Mix to a small plastic cup or paper cup.
- Add a drop or two of food coloring to the cup. Stir.
- Add 3 spoonfuls of the Cross-Linking Solution to your ball mix or slime mix and stir well.
- If the slime still feels too sticky, add a little more Cross-Linking Solution.
- Remove your completed slime from the cup.
The Science Behind the Fun:
Glue is a polymer, which is a long chain of molecules linked together, like a chemical chain. The polymer formed by water and glue is called polyvinyl acetate.
The Borax solution is called a cross-linking substance, and it makes the glue polymer chains stick to each other. Eventually, all the chains are bound together and no more cross-linking solution can be taken up.
To finish the slime kit, fill the plastic bin with the ingredients you put together, including jars of ingredients, instructions, plastic spoons, and mixing cups (optional.)
(Adapted from Kitchen Science Lab for Kids)
Grab an extra bag of cranberries this Thankgiving! Kids can use it to reveal invisible messages they write with baking soda and water.
-around 2 cups of cranberries
-small paintbrush, Q-tip, or lollipop stick
Safety tips and Hints:
Boiling the berries should be done by an adult. Keep the lid on the pan, since the air pockets that make cranberries float can also make them explode. Kids can take over once the juice is cool.
When playing with cranberry juice, aprons or old clothes are a good idea, since it stains!
Step 1. Cut a cranberry in half and observe the air pockets that make it float.
Step 2. Boil the cranberries in about three cups of water for 15 to 20 minutes, covered. Listen for popping sounds as the air in the cranberries heats up and they explode.
Step 3. Crush the cooked berries and push the liquid through a sieve or colander to collect the concentrated cranberry juice.
Step 4. Allow the juice to cool and pour it into a casserole dish or cake pan big enough to hold a piece of paper. If your cranberry juice seems thick and syrupy, add a little water, so that it’s thin enough to soak into paper!
Step 5. Test the paper you want to use by cutting a small piece and soaking it in the cranberry juice. If it stays pink, it will work, but if it turns blue or gray, try some other paper.
Step 6. Add a few teaspoons of baking soda to 1/3 cup of warm water and stir well. Don’t worry if you can still see some baking soda.
Step 7. Using a Q-tip, paintbrush, or a homemade writing tool, use the baking soda solution as ink to write a message on your paper. It may take a little practice, so don’t get frustrated.
Step 8. Let your message air dry, or speed things up with a blow dryer.
Step 9. To reveal your message, place your paper in the cranberry juice and see what happens!
*What other natural acid/base indicators could you use to do this experiment? What else could you use as ink.
The Science Behind the Fun:
Cranberries contain pigments called anthocyanins (an-tho-SY-a-nins,) which give them their bright color. In nature, these pigments attract birds and other animals to fruit. This is important because animals eat the berries and spread plants seeds from one place to another.
These pigments, called flavanoids, change color when they come in contact with acids and bases. Cranberry juice is very acidic, and the pigment is pink in acids, but when you add it to a base, it turns purple or blue.
Baking soda is a base, so your baking soda message will turn blue when it comes into contact with the pigments in the cranberry juice. Eventually, when enough cranberry juice soaks into the paper, it will dilute the baking soda, turning the pigment back to red and your message will disappear!
There are over 300 kinds of anthocyanins which are found in many fruits and vegetables including blueberries, red cabbage, grapes and blueberries. Scientists believe they may have many health benefits.
We have bags full of candy at our house, and I’d like to see them disappear as quickly as possible. Here are a few science experiments we tried, substituting candy for other ingredients:
Candy Chromatography: We put candy in water and used coffee filters to separate out the colors, via capillary action.
Candy-drinking plants? We dissolved candy in warm water and added white carnations with cut/split stems to see whether they’d change color as the flowers drew the water up into their petals.
Candy Vegetable Vampires: We tried the same experiment with Napa Cabbage, via the Vampire Vegetables experiment in Kitchen Science Lab for Kids.
We’re also going to freeze candy in ice and make Tie Dye milk with Skittles!
What could you try with your candy?
Here are ten quick and easy experiments to make your Halloween even more fun and memorable!
Click on these links for instructions on how to make:
Here are a few of my favorites!
You can find more experiments by scrolling down on my website!